The main focus of the research work of this group is concentrated in the field of photocatalysis and the kinetics of heterogeneous catalytic processes, but mainly photocatalytic processes with a view to their application to protection and remediation (decontamination) of the environment. Here the two basic directions are the purification of wastewaters from organic industrial productions, but also the removal of some inorganic pollutants – toxic ions of heavy metals, as well as air purification from volatile organic compounds (VOC) by means of their oxidative degradation. Thereupon special attention is paid to the synthesis of nano-sized oxide semiconductors, their modification applying various additives, as well as their characterization by physical and physic-chemical methods. Their characteristic features as photocatalysts of semiconductor type are juxtaposed with the data obtained by measurement of their photocatalytic activities and the respective correlations between rates and physical properties are established, as well as explanation of these correlations are put forward. This enables optimization of the conditions of their synthesis. The realization of the photocatalytic properties of destruction of contaminants in waters and in air under irradiation with ultraviolet light, visible light or their combination, i.e. the utilization of the solar radiation opens up a possibility to optimize the presently used photocatalytic reactors. The optimal configuration of these reactor setups is being searched for in view of improving it and selecting the optimal experimental conditions for testing the photocatalytic efficiency with a view to achieving complete neutralization of the contaminants. Another aspect under investigation is the combined photocatalytic oxidation of organic pollutants in the presence of mixture oxygen-ozone, whereupon it was established that the rate constants of the studied complete oxidation processes are increased several times. Photochromism is a reversible phenomenon involving photoinduced changes in the visible absorption spectrum.The chemical and photochemical reactions of photochromic compounds take significant place in advanced scientific research and development of new technologies due to their their potential applications such as information storage, electronic display systems, optical switching devices, ophthalmic glasses, displays, dynamic biosensors in storage systems for solar energy, catalysis, optics and electronics, bioelectronics and so on. We design and synthesize new spiropyrans, spirooxazines and diarylethenes. We study their physical and spectral properties. The heterocycles substituent in their structure promote coordination with metal ions, as well as allowing intercalating behaviour towards DNA. The process of supramolecular complex formation is used to regulate the optical and photochromic characteristics and also for build of the systems with photocontrolled properties.
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Veselin Iliev, Professor, PhD
Stela Minkovska-Dodova, Associate Professor, PhD
Katerina Zaharieva, Assistant Professor, PhD
Lyubima Bilyarska, Chemist Researcher